GB2391816A

GB2391816A - Heat and moisture exchange device with movable element

Info

Publication number: GB2391816A
Application number: GB0318974A
Authority: GB
Inventors: Simon Robert Payne; Surinderjit Kumar Jassell
Original assignee: Intersurgical Ltd
Current assignee: Intersurgical Ltd
Priority date: 2002-08-15
Filing date: 2003-08-13
Publication date: 2004-02-18
Anticipated expiration: 2023-08-13
Also published as: GB0218954D0; GB2391816B; DE10337503A1; DE10337503B4; GB0318974D0

Abstract

A tracheostomy heat and moisture exchange device (10) comprises a chamber (12) having a connection port (14) which, in use, is in fluid communication with the airways of a patient, an external port which, in use, is in fluid communication with the atmosphere, and a heat and moisture exchange element (16) mounted within the chamber (12) between the first and second ports for treating gas passing between the connection and external ports. The element (16) is movable, in the event of an increase in gas pressure within the chamber (12) during use, from a first configuration in which gas flowing between the connection and external ports passes through the element (16), to a second configuration in which gas flows between the connection and external ports without passing through the element. Preferably, one fastener 24 allows an element 16 to tilt under these conditions. Alternatively, one element one element can be pivotable (fig 9 and 10). The device can also have an openable and closable connection with a movable spigot 28 for oxygen. A further closable connection 30 can act as a suction port.

Description

Title -!morovements Relatino to Tracheostomv Heat and Moisture Exchange

Devices This invention relates to tracheostomy heat and moisture exchange devices.

During normal respiration, the upper airway warms and humidifies the inspired air so that when the air reaches the lungs, it has a constant temperature of approximately 37 and a constant humidity of approximately 44mg H20 per litre of air. During expiration, heat and moisture are reabsorbed by the upper airway, 10 thereby preventing dehydration.

The insertion of a tracheostomy tube into a patient deprives the patient of those functions normally carried out by the upper airway. Any loss of heat and/or moisture can lead to serious complications, notably damage to cilia and mucous 15 glands. This in turn may result in the retention of sputum and atelectasis, production of mucous plugs and possible tubal occlusion.

For the above reasons, a variety of devices are used to heat and humidify the air inspired by the patient and prevent the loss of heat and moisture by the patient on 20 expiration. One such device is a heat and moisture exchange (HME) device comprising HME elements through which the inspired and expired air passes.

A problem associated with conventional tracheostomy HME devices is that the HME elements can become blocked by an excessive mucous build-up. Such a 25 blockage inhibits a patient's breathing and this in turn can lead to the build-up of pressure within the patient's airways and the HME device. This build-up of internal pressure may continue until the patient fails to exhale, stimulating a gagging reflex in the patient and precipitating a cough. A powerful cough may displace the HME element completely, thereby reducing the pressure, but this may not occur until a 30 particularly high pressure is achieved and may lead to loss of, or damage to, the HME element.

There has now been devised an improved tracheostomy heat and moisture exchange device which overcomes or substantially mitigates the abovementioned and/or other disadvantages associated with the prior art.

According to a first aspect of the invention, there is provided a tracheostomy heat and moisture exchange device comprising a chamber having a connection port which, in use, is in fluid communication with the airways of a patient, an external port which, in use, is in fluid communication with the atmosphere, and a heat and 10 moisture exchange element mounted within the chamber between the first and second ports for treating gas passing between the connection and external ports, wherein the element is movable, in the event of an increase in gas pressure within the chamber during use, from a first configuration in which gas flowing between the connection and external ports passes through the element, to a second 15 configuration in which gas flows between the connection and external ports without passing through the element.

The tracheostomy heat and moisture exchange device according to the first aspect of the invention is advantageous principally because in the event of a build-up of 20 pressure within the chamber, the element is able to move to relieve this pressure rather than allowing this pressure to buildup until either the patient coughs or turns blue as a result of the occluded airway, which could be fatal, or the element is ejected from the chamber. The element is therefore less likely to be lost or damaged and the pressure within the chamber is released at a lower pressure 25 than that of conventional devices, which is clearly safer for the patient.

The element will typically be cylindrical. The element is preferably deformable and is preferably received within the chamber with a close fit. The element is most preferably mounted adjacent to the external port and therefore has an external 30 surface which faces towards the external port and an internal surface which faces away from the external port. The element may be mounted in any suitable manner

within the chamber provided that the element is able to move to the second configuration should the gas pressure within the chamber exceed a certain threshold. 5 In one suitable mounting arrangement the device may include a support which is disposed adjacent the internal surface of the element, and a retaining member which is positioned, in use, adjacent the external surface of the element. The support and retaining member may have any arrangement that allows rotation and/or deformation of the element when the gas pressure within the chamber 10 reaches a certain level, such as the support being disposed adjacent the centre of the element and the retainer being positioned, in use, to one side of the centre of the element.

The support preferably comprises a narrow pillar, most preferably aligned axially 15 along the centre of the chamber, and the retaining member preferably comprises a semi-circular member, most preferably aligned in the plane of the external surface of the element. One end of the retaining member is preferably hingedly mounted to the periphery of the external port, and the periphery of the external port preferably includes an opening which receives the other end of the retaining 20 member, most preferably with a snap fit.

Alternatively, the element may either be pivotally or hingedly mounted within the chamber. In such a case, the element is preferably encapsulated within a retainer casing which is pivotally or hingedly mounted within the chamber. The retainer 25 casing preferably includes openings which allow the passage of gas through the element. The chamber preferably has one connection port and two external ports in the form of a T-piece with the connection port preferably branching perpendicularly 30 from the chamber. The connection port is preferably adapted for connection to a tracheostomy tube. In addition, the chamber may include a supply port for the

supply of additional gases such as oxygen. The supply port is preferably rotatable with respect to the chamber. This is advantageous because even if the orientation of the chamber with respect to the gas supply alters, the supply port can rotate and maintain its orientation with respect to the gas supply. This allows the patient 5 a larger degree of movement and reduces the likelihood of a connection tube between the supply port and the gas supply becoming bent or twisted. In preferred embodiments, the supply port is positioned centrally on the device so as to minimise any off-centre loading which might otherwise be a source of discomfort for the patient.

The supply port preferably takes the form of a spigot, which is preferably pivotally mounted relative to the chamber. This may be by means of a housing which receives the spigot in such a way that the spigot is rotatable relative to the chamber. The spigot preferably comprises a cylindrical portion, which is received within a corresponding housing mounted on the chamber, and a connection port adapted for connection to a gas supply. The spigot preferably has vents which correspond to openings in the wall of the chamber. The housing may be formed so that the 20 spigot is rotatable between a first position in which the vents are in fluid communication with the chamber and a second position in which the vents are closed off, preferably by the housing.

Any of the features described above may be incorporated in a device according to 25 the invention. In addition, the chamber may include a suction port and preferably also a plug for the suction port which may be hingedly mounted relative to the chamber. The invention will now be described in greater detail, by way of illustration only, 30 with reference to the accompanying drawings, in which

Figure 1 is a perspective view of a first embodiment of a device according to the invention; Figure 2 is a sectional view along the line 11-ll in Figure 1; Figure 3 is a view similar to that of Figure 1 with a HME element in a release position; Figure 4 is a view similar to that of Figure 2 with the HME element in a release 1 0 position; Figure 5 is a side view of the first embodiment with an oxygen spigot in a first position; 15 Figure 6 is a view similar to that of Figure 6 with the oxygen spigot in a second position; Figure 7 is a view similar to that of Figure 1 with the oxygen spigot in the second position; Figure 8 is an exploded perspective view of the first embodiment; Figure 9 is a close-up perspective view of a second embodiment of the device according to the invention; and Figure 10 is a view similar to that of Figure 9 with the element in a release position. Figures 1 and 2 show a first embodiment of a tracheostomy heat and moisture 30 exchange (HME) device according to the invention which is generally designated 10. The HME device 10 has the form of a tubular T-piece and comprises a

cylindrical chamber 12 and a cylindrical connection port 14 branching perpendicularly from the centre of the chamber 12. The HME device 10 is typically injection moulded in polypropylene.

5 The chamber 12 and connection port 14 both have open circular ends which are in fluid communication with one another. The two open ends of the chamber 12 are dimensioned to each receive a cylindrical HME element 16 with a close fit. The HME elements 16 are made of a relatively deformable material so that the HME elements 16 can be compressed to a certain extent.

The chamber 12 includes two support bars 18 which extend diametrically across the interior of the chamber 12 from either side of the connection port 14.

Extending axially along the chamber from these support bars 18 towards the open ends of the chamber 12 are central supports 20. These central supports 20 have 15 the form of narrow pillars which maintain the inwardly facing surface of the HME elements 16 in the correct position during use.

One open end of the chamber 12 includes a full retainer 22 and the other open end of the chamber 12 includes a partial retainer 24. The full retainer 22 20 comprises a ring portion with two radially extending arms, as shown more clearly in Figure 8. One end of the full retainer 22 is hingedly fixed to the periphery of the open end of the chamber 12, and the diametrically opposite side of the open end of the chamber 12 includes an opening into which the other end of the full retainer 24 is received with a snap fit to close. The full retainer 22 is closed once the HME 25 element 16 is in position within that end of the chamber 12. In this closed position, the full retainer 22 bears against the outwardly facing surface of the HME element 16, and retains the HME element 16 in the correct position during use.

The partial retainer 24 comprises a semi-circular member with two short, outwardly 30 extending arms at each end thereof. One end of the partial retainer 24 is hingedly fixed to the periphery of the open end of the chamber 12, and the diametrically

opposite side of the open end of the chamber 12 includes an opening in which the other end of the partial retainer 24 is received with a snap-ft to close. The partial retainer 24 is closed once the HME element 16 is in position within that end of the chamber 12. In this closed position, the retainer 24 bears against the outwardly 5 facing surface of the HME element 16, and retains the HME element 16 in the correct position during use.

In use, the connection port 14 is connected to a tracheostomy tube (not shown in the Figures) fitted in conventional manner to a patient's trachea. During 10 inspiration, air from the atmosphere is drawn through the two open ends of the chamber 12' through the HME elements 16, through the connection port 14, through the tracheostomy tube and into the lungs of the patient. During expiration, the expired gases are urged by the lungs of the patient through the tracheostomy tube, through the connection port 14, through the HME elements 16, through the 15 two open ends of the chamber 12 and into the atmosphere.

On inspiration, the air passing through the HME elements 16 and into the patient's lungs is heated and humidified by the HME elements 16 to a temperature of approximately 37 and a humidity of approximately 44mg H20 per litre of air. On 20 expiration, the HME elements 16 remove and retain heat and moisture from the air passing through the HME elements 16 and into the atmosphere. In this way, the HME elements 16 mimic the functions of the upper airway, thereby reducing the risk of dehydration.

25 Turning now to Figures 3 and 4, if the passage of air through the HME elements 16 becomes hindered or blocked for some reason during use, the air pressure within the HME device 10 and the tracheostomy tube will start to increase. After a certain rise in internal pressure, the HME elements 16 will be urged outwards by the internal pressure. The HME element 16 at the end of the chamber 12 fitted 30 with the full retainer 22 will remain in place. The other HME element 16, however, is retained only by the partial retainer 24. Because the lower part (as viewed in

the Figures) of this HME element 16 is not constrained by the partial retainer 24, that element 16 may, once the internal pressure is great enough, deform and/or rotate to the position shown in Figures 3 and 4. A clear airway will therefore be formed above and below that HME element 16 (as viewed in Figures 3 and 4) 5 reducing the likelihood of the HME element 16 being ejected from the HME device 10 and preventing any further build-up of pressure within the HME device 10.

Integrally formed on the underside of the chamber 12 is a spigot housing 26 which comprises formations for receiving a spigot 28 with a snap-fit, as shown more 10 clearly in Figures 5, 6, 7 and 8. The spigot 28 is a tubular T-piece having a cylindrical chamber with closed ends and a connection port branching perpendicularly from the centre of the spigot chamber. The spigot 28 is typically injection moulded in high density polyethylene (HOPE). The chamber of the spigot 28 is received within the spigot housing 26 with a snap-fit so that the chamber of 15 the spigot 28 is able to rotate within the spigot housing 26.

The upper surface of the chamber of the spigot 28 (as viewed in Figure 8) includes two vents which are located either side of, and are in fluid communication with, the connection port of the spigot 28. These vents have corresponding openings in the 20 underside of the chamber 12 so that the connection port of the spigot 28 is in fluid communication with the interior of the chamber 12.

The spigot housing 26 and spigot 28 may be founded so that when the spigot 28 is rotated to a position where the connection port of the spigot 28 is adjacent the 25 connection port 14 (see Figure 5), the openings in the underside of the chamber 12 are sealed by the opposite side of the chamber of the spigot 28 to that on which the vents are located.

In use, if a patient requires extra oxygen, or any other gas, the spigot 28 is rotated 30 to the position shown in Figures 6 and 7 and connected to an oxygen supply (not shown in the Figures). Since the spigot 28 is able to rotate relative to the chamber

12, the patient is allowed a greater degree of movement with the connection to the oxygen supply prevented from becoming twisted or bent. If a patient does not require extra oxygen, the spigot 28 is rotated to the position shown in Figure 5.

5 Additionally, the HME device 10 includes a suction port 30 (see Figure 8) in the wall of the chamber 12. The HME device 10 also includes a flap 31 hingedly fixed to the external surface of the chamber, and a plug 32 positioned on this flap 31 so that the plug 32 may be brought into and out of engagement with the suction port 30. In this way, the suction port 30 may be sealed by the plug 32 when not in use.

A second embodiment (shown in Figures 9 and 10) of a HME device according to the invention is identical to the first embodiment 10 save that the partial retainer 124 of the second embodiment is of a different form to the partial retainer 24 of the first embodiment 10. One end of the chamber 112 of the second embodiment is 15 shown in Figures 9 and 10. The partial retainer 124 comprises a framework casing which encapsulates the HME element 116 and is pivotally mounted within the end of the chamber 112.

In use, the partial retainer 124 and HME element 116 are in a normal operating 20 position, as shown in Figure 9. If the passage of air through the HME elements 116 becomes hindered or blocked for some reason during use, the air pressure within the HME device and the tracheostomy tube will start to increase. After a certain rise in internal pressure, the partial retainer 124 and HME element 116 will rotate to a release position, as shown in Figure 10. A clear airway will therefore be 25 formed above and below the HME element 116 (as viewed in Figures 9 and 10) preventing any further build-up of pressure within the HME device 10. In addition, the HME element 1 16 will not be lost as the HME element remains encapsulated by the partial retainer 124.

Claims

1. A tracheostomy heat and moisture exchange device comprising a chamber having a connection port which, in use, is in fluid communication with the airways 5 of a patient, an external port which, in use, is in fluid communication with the atmosphere, and an element mounted within the chamber between the first and second ports for treating gas passing between the connection and external ports, wherein the element is movable, in the event of an increase in gas pressure within the chamber during use, from a first configuration in which gas flowing between 10 the connection and external ports passes through the element, to a second configuration in which gas flows between the connection and external ports without passing through the element.

2. A device as claimed in Claim 1, wherein the element is cylindrical.

3. A device as claimed in Claim 1 or Claim 2, wherein the element is deformable and is received within the chamber with a close fit.

4. A device as claimed in any preceding claim, wherein the element is 20 mounted adjacent to the external port and has an external surface which faces towards the external port and an internal surface which faces away from the external port.

5. A device as claimed in Claim 4, wherein the device includes a support 25 which is disposed adjacent the internal surface of the element, and a retaining member which is positioned, in use, adjacent the external surface of the element.

6. A device as claimed in Claim 5, wherein the support is disposed adjacent the centre of the element and the retainer is positioned, in use, to one side of the 30 centre of the element.

7. A device as claimed in Claim 5 or Claim 6, wherein the support comprises a narrow pillar, most preferably aligned axially along the centre of the chamber, and the retaining member preferably comprises a semi-circular member, most preferably aligned in the plane of the external surface of the element.

8. A device as claimed in Claim 7, wherein one end of the retaining member is hingedly mounted to the periphery of the external port, and the periphery of the external port includes an opening which receives the other end of the retaining member, most preferably with a snap fit.

9. A device as claimed in Claim 4, wherein the element is pivotally or hingedly mounted within the chamber.

10. A device as claimed in Claim 9, wherein the element is encapsulated within 15 a retainer casing, the retainer casing including openings which allow the passage of gas through the element.

11. A device as claimed in any preceding claim, which has the form of a T-

piece, the chamber having one connection port and two external ports, with the 20 connection port branching perpendicularly from the chamber.

12. A device as claimed in Claim 11, further comprising a supply port for the supply of additional gas.

25

13. A device as claimed in Claim 12, wherein the supply port is rotatable with respect to the chamber.

14. A device as claimed in Claim 13, wherein the supply port is rotatable between a first position in which the supply port is in fluid communication with the 30 chamber and a second position in which the supply port is sealed from the chamber.

15. A device as claimed in any Claim 13 or Claim 14, wherein the supply port takes the form of a spigot.

5

16. A device as claimed in Claim 15, wherein the spigot is pivotally mounted relative to the chamber.

17. A device as claimed in Claim 16, wherein the spigot comprises a cylindrical portion, which is received within a housing mounted on the chamber, and a 10 connection port adapted for connection to a gas supply.

18. A device as claimed in any one of Claims 15 to 17, wherein the spigot has vents which correspond to openings in the wall of the chamber.

15

19. A device as claimed in any preceding claim, wherein the chamber includes a suction port.

20. A device as claimed in Claim 19, wherein a plug for the suction port is hingedly mounted relative to the chamber.

21. A tracheostomy device substantially as hereinbefore described and as illustrated in the accompanying Figures.